The present invention relates to a vehicle control device and a vehicle control method.
Conventional types of automatic transmission for vehicles include one which uses a torque converter and one which uses a continuously variable transmission. Recently an automated MT (manual transmission) has been proposed. It is comprised of a system in which clutching and gear change are automated based on a manual transmission mechanism. A recent automated MT system in which a friction clutch (assist clutch) is provided between the input and output shafts of the transmission for keeping torque transfer during gear shift operation, is proposed (for example, see JP-A No. 2000-65199). Furthermore, a so-called twin clutch automated MT is proposed in automated MT systems. In the twin clutch automated MT, each friction type clutch is provided between an engine and each of plural input shafts; by switching the plural friction clutches (namely by clutch to clutch), a shifting is carried out from a gear position established by one input shaft to a gear position established by the other input shaft.
These automatic transmissions often use a power transfer mechanism which transfers and releases power in state of being lubricated with oil (lubricating oil or working fluid; hereinafter representatively called lubricating oil).
The lubricating oil not only has the primary function of lubrication but also functions as a medium for cooling generated heat, offering the advantage that it protects the power transfer mechanism from burnout.
On the other hand, when the power transfer mechanism is released, the lubricating oil works as a source of drag torque, thereby bringing the disadvantage that may cause deterioration in fuel efficiency and shift performance.